1. Field of the Invention
The present invention relates to an automatic Integrated Circuit (IC) mounting system for mounting a plurality of ICs on a printed circuit board in sequence.
2. Description of the Related Art
A plurality of IC's, such as Dual-in-line package (DIP) type IC's which comprise leads disposed side by side in row and projecting from each of the side faces of a box-shaped package, are mounted on a printed circuit board which is installed in various kinds of electronic devices, communication devices, and the like. An automatic IC mounting system is used for automatically mounting IC's in a printed circuit board during mass-production of a device comprising a number of such printed circuit boards. The IC mounting system inserts the leads of each IC into through-holes of the printed circuit board and every one of the leads of each IC must be inserted into the corresponding and correct through-hole.
The automatic IC mounting system of the prior art comprises a tridimensionally movable arm and an insertion head attached to the end of the arm. The insertion head comprises a picker having a pair of finger plates facing each other, for picking-up and holding an IC therebetween. The IC is picked up by the picker and conveyed toward a printed circuit board placed on a table at a predetermined location. When the IC is conveyed to a predetermined position above the printed circuit board, a pusher descends between the pair of finger plates and urges the IC held between the finger plates downward in such a manner that the IC leads are inserted into corresponding through-holes of the printed circuit board. Such an IC insertion operation is repeated by the system for a plurality of ICs to be mounted on the printed circuit board in sequence.
If one of the IC leads should be accidentally bent or distorted in the conveyance thereof or in the preceding manufacturing process thereof, the distorted lead cannot be inserted into the through-hole but will be bent back and folded upon the upper surface of the printed circuit board by the pressure of the pusher on the IC. The printed circuit board on which such misinserted IC is mounted cannot perform a predetermined function and must be scrapped. Therefore, after the mounting process for the ICs, all of the leads of the ICs are checked by a detection means to ensure that each lead is correctly inserted into the corresponding through-hole of the printed circuit board.
When a misinserted IC is detected by the detection means an alarm is actuated by the detection means and the operation of the system is stopped. An operator must then replace the misinserted IC with a new IC by hand before the operation of the IC mounting system can be restarted.
However, in accordance with the above mentioned automatic IC mounting system, the productivity of the printed circuit board is greatly lowered, since the flow of the IC mounting process is stopped when replacing the misinserted IC. Also, the reliability of the manual replacement operation by the operator is low since the new IC may be wrongly mounted at an incorrect position or an incorrect IC may be mounted.